Estimate my muzzle velocity ?

[gwtx]

My chrony is out of commission and I was interested to see what the "educated guesses" might be.
I'm shooting an 18"bbl (I think its' BA but not sure). Load is 123 sst seated 2.250 with 27.5 gr AR Comp, cci 450 primers, and both hornady and starline brass. Just a thread protector on the end of the bbl. The load is shooting very good, and I'm just curious about the MV. I'm guessing low to mid 2400 fps. Whatcha think? Thanks.

Don't ask what happened to the chrony

[A5BLASTER]

2340 to 2365

[VASCAR2]

Take a look at this thread.

http://www.65grendel.com/forum/showthread.php?16315-Data-for-AR-Comp-and-123-sst-s-in-my-new-18-quot-GB-barrel

[gwtx]

Thanks for the replies guys. I have looked at as many "reports" as I could find for that load and configuration. There is so much variation in the reported results. My rifle is for hog hunting, and the thermal scope is not the best for "target" shooting. It's difficult to get a "fine dot heat source". Most of my shots(at hogs) is around 100yds, and the POI at that range and at 175yds is consistent with the data for a "2400ish" MV. Doesn't matter much, since I really don't have to worry with holdovers at those ranges. I was just curious. Thanks vascar2 for the link to that post , and for the info included in it. I'm counting on getting a nice big cost of living increase in our social security, and then maybe I can get a MagnetoSpeed

[A5BLASTER]

Thanks for the replies guys. I have looked at as many "reports" as I could find for that load and configuration. There is so much variation in the reported results. My rifle is for hog hunting, and the thermal scope is not the best for "target" shooting. It's difficult to get a "fine dot heat source". Most of my shots(at hogs) is around 100yds, and the POI at that range and at 175yds is consistent with the data for a "2400ish" MV. Doesn't matter much, since I really don't have to worry with holdovers at those ranges. I was just curious. Thanks vascar2 for the link to that post , and for the info included in it. I'm counting on getting a nice big cost of living increase in our social security, and then maybe I can get a MagnetoSpeed

You will love the magneto speed. I just steeped up from the top end Caldwell to the magneto speed sporter.

I wanted the top end magneto speed but it was out of stock when I was making a large order from midway. So grab the sporter version. Really can't see how it could be any better.

[Popeye212]

You will love the magneto speed. I just steeped up from the top end Caldwell to the magneto speed sporter.

I wanted the top end magneto speed but it was out of stock when I was making a large order from midway. So grab the sporter version. Really can't see how it could be any better.

There's a couple of accessories that would come with that V3 that would be handy. When I get around to I am going buy the case,rod and taper barrel kit.

[dl126]

The way I zero thermal ....

Use an all black target. (I use shoot and see's)
Cut a 1" square piece of aluminum foil.
Tape only 1 side of the foil to the target and make sure it is not lying flat against the black backing. (Pull it away slightly)
Also make sure to put the foil "shiny" side out.
Place the target in direct sunlight.
Put scope in White Hot mode.

Using this method, at 36 yards I can plainly see that 1" square of aluminum foil.
The target will be white, and the foil will be black.
Under the right conditions, you'll even see "black" bullet holes upon impact.

ETA: I don't reload, but my 18" with Hornady Black shoots 2430 FPS.

[imaguy3]

you could estimate it fairly easily... shoot a group at 100... shoot a group at 300 using the same aiming point and measure the drop... plug all the info into a ballistics calculator and adjust the velocity to match.

[Sinclair]

you could estimate it fairly easily... shoot a group at 100... shoot a group at 300 using the same aiming point and measure the drop... plug all the info into a ballistics calculator and adjust the velocity to match.

This works most of the time, but be aware that some bullet manufacturers seem to get a little optimistic with their BCs which means that eventually you have to fiddle with both MV and the BC to force the Ballistic Calculator's results to fit your field results. Just my experience with trying to cheat; however, the upside is that the results you will eventually arrive at will be more accurately tuned to your rifle/ammo/field conditions than the manufacturer's published charts. Definitely worth the effort if you do not have a Chrono!

[gwtx]

The way I zero thermal ....

Use an all black target. (I use shoot and see's)
Cut a 1" square piece of aluminum foil.
Tape only 1 side of the foil to the target and make sure it is not lying flat against the black backing. (Pull it away slightly)
Also make sure to put the foil "shiny" side out.
Place the target in direct sunlight.
Put scope in White Hot mode.

Using this method, at 36 yards I can plainly see that 1" square of aluminum foil.
The target will be white, and the foil will be black.
Under the right conditions, you'll even see "black" bullet holes upon impact.

ETA: I don't reload, but my 18" with Hornady Black shoots 2430 FPS.

dl126 Thanks for the info. I use the aluminum tape, but had not thought about separating it from the target to get the temp differential greater. I tilt the target to get the sunlight on it. Just kinda hard to determine the exact center of the image.
Thanks again for the tip, I'll try it. What scope are you using?

[gwtx]

you could estimate it fairly easily... shoot a group at 100... shoot a group at 300 using the same aiming point and measure the drop... plug all the info into a ballistics calculator and adjust the velocity to match.

I don't have a spot on my place to shoot 300yds conveniently and safely, and don't know of a range nearby. I probably can't shoot well enough at 300yds to make an accurate determination Thanks for the reply

[gwtx]

ETA: I don't reload, but my 18" with Hornady Black shoots 2430 FPS.
Factory 123 SST's, 123 Black, and my hand loaded 123 SST's all shoot the same point of impact, so I'm guessing my MV is around the 2430 you get from the Blacks. Thanks for the reply.